| 摘要 |
PURPOSE:To obtain an offset quantity correction circuit having high accuracy with simple constitution by initializing the detection part of an X-ray CT device, and correcting by calculating data passing for a certain period and re-initialized data. CONSTITUTION:A switch 1a operates for a period of t0-t1 and that of t4-t5 so as to intialize, and an AD convertor 3 gives an output D1 of a detection circuit 1 when an input is not added for a computer 6 at a t2. D1/(t2-t1)=D2 is calculated, and stored in a characteristic memory 7. After the detection circuit 1 has been initialized at a period of t4-t5, an input is fed to the detection circuit 1 for a period of t6-t7, an output D3 is fed to the computer 6 at a t8, and D3- D2(t8-t5)=D4 is calculated. Assuming that t8-t5=t2-t1, then D4=D3-D1 is derived; therefore offset characteristic correction can be achieved extremely easily. Thus an offset quantity correction circuit, in which errors after correction is extremely small, can be obtained. |
